I have an external hard drive in a case, connected to my pc with USB cable and power supply. I turned on the drive today and it will not boot up, i.e., it's not recognized in windows and it doesn't sound like it's spinning. Normally when it worked before you could hear it quite well and it got rather warm when it was operating. The last 2 or three times I turned it on it seems like it's taken progressively longer and longer each time to boot up. The last time it worked I had to leave the room for a half hour for it to work itself up. I do know one time I turned it on it seemed like it had to crank itself up, i.e., it would make a whirring noise for a few seconds then stop; then make a whirring noise for a bit longer, etc.. Then it finally got itself going. It's late at night and I haven't had time to take it out of the case so I can't say for sure what brand the drive is, but I remember the case was pretty "cheap."
I sure hope this isn't a drive crash, I have tons of very important stuff on it. My son the techie told me it likely isn't a drive crash because even if data was lost the drive would still be spinning (?). I tried plugging it into my laptop and it would boot there either.
Sorry for lack of specific data on the drive; I just haven't had time to take everything apart. Any ideas?
Thanks in advance.

From what you have Stated. It may be the Power Supply Board on the External Hard Drive Case Dieing. Or it has Died. Rather than your Hard Drive Crashing. But that is what you have Related to us. If you have a way of testing the Power output in the External Case Check it out First. That will tell you if you have power or Not. It is Rare but Check the Power Pack that Plugs into the External Case. It may have burned Out. That is if you have one that Plugs into it. Some just have the Power Cord that just plugs into the Unit. If you get Good Readings from all of that then you may want to take the Hard Drive Out and take it to a Tech and see if the Drive is Bad or Not.

Also if you still have a Warranty on the Drive then Have it Sent in under it. They also may be able to get your Information off the Drive and put it onto DVD'S or what ever type of Media you Want. Or even transfer it to the New Unit like it had nothing done to it.

usually when an external drive is connected to the computer, the more the data it can hold, the longer the boot up sequence takes at least this has been the case in my experiences the computer is probably still booting but is just going to take an extended period of time to do so. You could always just connect it after booting up though when you need to use it.